Posted
by
michaelon Tuesday March 12, 2002 @10:26PM
from the riding-the-torch dept.

jonerik writes: "Former NASA engineer Homer Hickam (perhaps best known for his 1998 memoir "Rocket Boys," which was turned into the 1999 motion picture "October Sky") has this article in Technology Review in which he advocates that the U.S. revive its nuclear rocket program of the '50s and '60s, arguing that nuclear-powered rockets are the only realistic way of opening up the rest of the solar system - particularly Mars - to human exploration."

To propose that we spend more money on NASA (with cutbacks already planned), the "nuclear fission" rocket may just be a pipe dream. It's hard to convince people that we need to explore space when the topic of the day is terrorism.

To propose that we spend more money on NASA (with cutbacks already planned), the "nuclear fission" rocket may just be a pipe dream. It's hard to convince people that we need to explore space when the topic of the day is terrorism.

Well, they go hand in hand. The technology from space exploration affects our lives in thousands of big and small ways every day. The integrated circuit was first mass-produced for space exploration reasons. And it's a lot easier to peel my fried eggs off Teflon than it is off cast iron.

Any advance in getting the general public to get over their Three Mile Island and Chernobyl paranoia will require nuclear-powered triumphs.

Idiot hippy environmentalists speak of cutting dependence on (foreign) oil by moving to electric cars. That'd be nice. How do you intend to handle California's power crisis (remember, 2 years ago) when 10,000,000 Los Angeles commuters are plugging in their cars every night?

The very same environmentalists who scream about oil and air pollution are also at the mass rallies to ban genetically-modified agriculture. GM corn is probably the most economically feasible way, at this point, to make large quantities of methanol, which could replace gasoline very easily, simply retrofitting existing vehicles and infrastructure. These people also scream that we have to solve world hunger before we feed our cars. (My opinion? Theses savages are stupid enough to breed when they can't feed themselves, let alone their larvae. It doesn't take education or literacy to understand the problem; a below-average human intelligence should readily grasp the situation. It's not my problem, and I resent you attempting to make it my problem.)

Nuclear power is the only viable solution. And the proles have discarded it because they're too simple to understand that blaming nuclear power for Chernobyl would be like blaming gasoline for a car accident. Chernobyl, Three Mile Island and the vast majority of car accidents are caused by imbeciles, not the fuel source.

What's all this got to do with terrorism? Simple. The sooner we get off foreign oil, the sooner we can dig a moat around the Middle East and let them do their thing in isolation from the civilized world. And if funding NASA to build huge nuclear public-relations projects which will inevitably bring us other technologies as a consequence, I'm all for it.

Go ahead. Mod me down. But I'm right, and all the politically-correct simpering you might want to do won't change the facts.

...as if electric power were magicked out of the air. It turns out that they're right about the GM plants but for mostly the wrong reasons. GM agriculture is running into all kinds of problems including - tahdahh - lower yields. It's a research cul-de-sac so far.

she said:"I've had 4 kids, 3 already died, I want to have about 10, and I expect 2 to survive"

this is a very rational probablistic view, not a stupid women at all.

the indians as a nation ARE stupid, since they allow the situation to reach this point, but the "common" people are usually not stupid when it concerns their own survival, or they wouldn't be so common.

and wether you like it or not, it IS your problem, since hungry people bite harder.

(note I don't say sending rice or whatever is a solution, I believe technological and political methods must be used jointly, with threat of force when needed, but in any case, it IS your problem)

For one thing, the Chernobyl nuclear plant was a disaster waiting to happen. Between the dangerous design of the reactor and the fact there was no containment dome, no wonder the disaster was so bad.

The Three Mile Island accident was proof that Western nuclear plant designs worked. Note that even though the fuel rods partially melted down the containment dome was nowhere close to being breached; the radioactive release was equivalent to the radiation dose you get on a single five hour trancontinental flight from Los Angeles to New York at 30,000 feet.

By the way, our nuclear waste problem is minor compared to the former Soviet Union, where they actually stored nuclear waste in open pits for many years. (eek!)

He is 100% correct in his assessment that nuclear power is our only currently viable option to explore the rest of the solar system.

Unfortunately, people are so freaked out about anything with the word "nuclear" or "reaction" attached to it the only way they would ever put a dime in it is if it was called "The Wonder Drive" or "Warp Drive". The really sad part about that is nuclear powered rockets really wouldn't be that dangerous. The most dangerous part about them would be getting the fuel off planet, which is not as dangerous as it sounds.

When someone first thinks about nuclear waste, one of the first reactions is, "why not just launch it into space?" I haven't happened to come upon the argument against it, but I imagine it goes like: sending stuff into space is far more expensive and polluting than people imagine.

But this would be perfect -- sure, you'd be making more nuclear waste, but you'd be sending it into space in the process! That's not hard to understand.

I think there is every reason to worry about dangers, though. Rockets do blow up (with current technology) and if they had radioactive materials onboard that would mean many, many deaths (mostly indirectly through increased cancer).

I imagine that nuclear rockets could be considerably safer than chemical rockets, since my vague impression is that they wouldn't be as explosive. But many of the standard ways that nuclear reactors are made safe -- mostly through containment of various sorts -- would be hard to do in a rocket.

You are worried about nukes going off on US soil? Guess what, It has already happened. Repeatedly. The difference is that the test site was in the central US as opposed to one of the coasts. But that doesn't mean thousands of Americans didn't die from it. These tests were done upwind of a town; they died of cancer...

(Area 51 is well known, but have you ever wondered where that name came from? It is a bomb grid reference. The place is radioactive.)

It is no secret, but since it hasn't gotten air time on the news alot of people don't seem to know about this. I have relatives who could see the mushroom clowds periodically from their homes.It's almost kind of like the rocket engine tests that produce huge clowds visable from Sandy, Utah. Alot of people have seen them, but few non-locals know about it.

The problem with launching nuclear waste into space is that the stuff is heavy. Remember, it's made out of stuff higher than lead on the periodic table.

Except that fission products arn't transuranic elements.They are more likely to be from the Rubidium to Xenon row on the periodic table. Indeed if you were to get symetrical fission of Plutonium you'd get Silver. (As an unplesently radioactive isotope.) Heavy Strontium and Iodine are also common fission products.

Nuclear does scare folks. The medical imaging of NMR (Nuclear Magnetic Resonance) got changed to MRI (Magnetic Resonance Imaging) because people were freaking out about the 'nuclear' part. Even though it was passive reading of nuclear states, not actively nuking patients.

There's a good writeup on:

http://www.urbanlegends.com/science/mri_not_nucl ea r.html

The "nuclear rocket" folks could take a page from their book. Call this "water rockets" or such and downplay the nuke, upplay the 'tea kettle' method (or what have you).

I applaud your post. But don't limit yourself to nuclear paranoia just for spaceships. There's still a lot of squalking about the facility in Nevada to store terrestrial nuclear waste. There's just too much politically associated with bad things like three mile island, etc. People demand we cut consumption of fuel, but don't want to take a relatively cheap / efficent / clean fuel like nuclear power.

Nuclear power could solve lots and lots of energy problems, and really bring down total cost of electricity. Plenty of nations have nuclear power as their primary source of electricity (france, for instance). If electricity prices really dropped, and battery technology got better, we could finally have lots of electric cars. Lots of electric cars means we could break the grasp of OPEC and all those other nations which control U.S. interests in oil. All I see in nuclear power is profit for everyone.

And, because i know it's coming, a rocket, laden with radioactive material, that explodes and scatters nuclear waste, would probably increase cancer rates about as much as the huge plumes of smoke that we dump into our atmosphere by burning all those chemicals to get into space using conventional fuels.

While NASA's funding is down, the funding to nuclear programs, specifically, is UP. This could mean (a) Bush's energy plan is looking everywhere for power or (b) somebody realized this was the next propultion system.

While NASA's funding is down, the funding to nuclear programs, specifically, is UP. This could mean (a) Bush's energy plan is looking everywhere for power or (b) somebody realized this was the next propultion system.

The DoD budget is also up. The "next" propulsion system is in use already (or very close to it). Look up Rocketplane (look at the "out and back in" military record of the president and founder), or the "Aurora" sightings (be aware like all outside accounts about classified aircraft there are also plenty of conspiracy BS about it, but some of it is very reasonable and documented). Even if neither of those is the primary focus of the US military getting to space, I have no doubt at all that they have their ways, other than the old reliable Titans.

Other key facts to look at include the fact that all the US military projections of near future battles work on the assumption of US space superiority and ability to fly birds on demand. I seriously doubt that the US DoD depends that much on NASA for such things.

Drawbacks? Simple - the US military dosen't want anybody else in space, or it loses that crucial high ground. That means other countries and civilians (including corporations like airlines, FedEx and hotels that *want* to get up there) are left out. Also NASA. The other aspect is that all military applications are pretty much limited to orbital to LaGrange space. That means that everything from the moon to the rest of the system is considered "useless".

Does this mean that I think there is a vast conspiracy and nobody will be able to get to space without MiBs knocking on the door and burning the plans? No. Do I think that there is an active discouragment of "uncontrolled" development of space technology? Yes... to what degree, I don't know. It may be very mild and just what we see publically (lowering NASA's budget), or it might be very strong (the DoD buying up tech companies that show promise). Regardless, it keeps me and my children out of space (unless they wind up wearing a US uniform), and that pisses me off.

First, there's the well-documented high failure rate [go.com] of launch vehicals -about 5% for the US, 10-20% for rest of the world. This figure doesn't include experiments or tests.

Second, the atmospheric reentry of one lost rocket schlepping clicking-hot material up the well can lead to the atomization and dispersal of that material in the atmosphere, transforming the earth into a mutants' menagerie.

The Space Shuttle has experienced a lower failure rate than the rest of US launchers, about one in one hundred [fotuva.org].

There was an uproar a few years ago, about the Cassini probe. That probe, containing over 32 KG of plutonium, was lifted by a launcher which, at the time, had a one in twenty failure rate, and was due for another.

Additionally, there have already been three catastrophic failures of launchers with plutonium-containing payloads, resulting in world-wide atmospheric dispersal of a hundreds of curies worth of plutonium.

Personally, I don't have a problem with the idea nuclear power or fission-powered space travel. But there remain serious development before it becomes considerably safer. This isn't a marketing campaign, you can't convince knowledgeable people with images of spouting teapots, not when life on this planet is at risk. Nor will risk management white-wash keep people from realizing there's a definite, likely risk that people will die from an accident. [I work in risk management.]

So, what's more important, do we need to do this now, now, now? Or can it wait a decade or three, until we have nuke power better figured out? My vote is to wait a bit.

Thats only assuming that you use the nuclear rocket part to take off. This is unlikely. A more likely case is it will be lifted by manual methods, piece by piece, assembled in orbit and then operated a safe distance from the earth. Even if these parts explode in takeoff it will not have any real radioactivity risk assuming that it uses normal fuel (ie uranium, not plutonium) since the half-life of U-235 is almost a billion years and U-238 is billions of years (longer half-life means less radioactive and billions of years means very, very small radioactivity). In newly built nuclear power plants you can walk around near the reactor without any radiation risk due to this fact. Of course once you start up, it has radioactive daughters and transuranics that make it radioactive.

IIRC the greatest health threat that has happened in past nuclear detonations or accidents like Chernobyl are fission by-products like Iodine-131. I don't believe U bioaccumulates, so it's probably not as much of a concern except for very high direct exposure. I am not a chemist (or even a real engineer), but it seems to me that with fresh Uranium fuel accidentally released into the environment from something like an ceramic fuel pellet, either the pellet is intact in which case the by-products aren't being released into the environement, or the pellet is destroyed in which case they are being produced at a very slow rate (given by the long,long half life of the fuel isotopes).

Personally, I'd be more concerned with mine and mill tailings from Uranium production, which contain the full range of decay products in large quantites, than the release of freshly refined fuel.

On one hand, I think it is naive to think you can have a program which launches radioactive fuel into orbit on a regular basis without some release of radioactive materials into the environment. On the other hand, while I'm generally supportive of enviornmental positions, arguing a zero tolerance for release of radioactivity into the environment is to vague a position for me to support. What kind of radioactivity? What form will it take? At what point in production or use will it be released?

Correct me if I'm wrong, but I'm under the impression that sending the fuel off planet is pretty dangerous. If a second Challenger were to happen, all those nuclear materials would be spread out in the atmosphere, which sounds pretty dad-gum dangerous.

Depends how well protected the fuel was. Even with the violence of the Challenger explosion identifiable pieces of wreckage were recovered. Aircraft carrying nuclear weapons have exploded before now.

It may be a fine point but the range safety officer at a launch complex does not "blow up" the rocket. The range safety systems on rockets are thrust termination systems, designed to terminate powered flight. The goal is to shut down the engines, not to blow up the rocket into many small pieces. This usually involves shaped charges that open the casings of solid fuel rocket motors and the fuel and oxidizer tanks of liquid fuel rocket motors. The desired end result is that the rocket falls in a ballistic trajectory into a safe impact area and does not endanger people on the ground. The range safety officer has an "impact predictor" display that shows where the rocket would land if all of the engines failed at the same time. His job is to push the big red button if there is a risk that the rocket could stray from its predicted trajectory. It may look like they "blew up" the rocket, but that isn't what happened.

Uranium is not very radioactive, neither is plutonium, and they are ALPHA RADIATORS, even a damn sheet of paper would be enought to shield you from it, only way to get a cancer would be to inhale the stuff and get it stuck in your lungs for a long time, and as you said, it's molecular weight is enormous, it won't stay airborne long enough for people to really breath too much of the stuff.

If you has a solid lump of metal the risk is low. However if you have dust, is much more dangerous because it can either be ingested directly or react to form compounds which can be ingested.

What sets this apart from most arguments for space exploration (at least in the popular media) is that he argues based on a need (energy) rather than talking about exploration and science for its own sake.

he argues based on a need (energy) rather than talking about exploration and science for its own sake.

No wonder nobody else replied - you mentioned a factor that was actually important. (-:

Solar power, wind power and stuff is nice, but the bottom line is there cannot possibly be enough of it even for our current needs even if we coated the entire countryside with collectors - so we need some new source of energy.

Unfortunately, "nuclear" and "fission" have been dirty words in this country for the last three decades.
This didn't stop nuclear submarines. I think it is more the idea of nuclear rockets that make people think of cold war times. We trust the lifes of many members of the navy to work around nuclear reactors, only PR would be necessary to gain back the confidence of the people in nuclear powered rockets too.
Stig.

If I remember correctly, the first group of nuclear submarines to actually enter the fleet put to sea in the early 60s, four decades ago, when our friend Mr. Atom was going to make the whole world a better place. Frankly, I still think that Mr. Atom and the power he provides are great things.

[...]only PR would be necessary to gain back the confidence of the people[...]

Except that for every "Nuclear-powered space vehicles are safe and effective" commercial NASA would produce, the Sierra Club, Greenpeace, the World Wildlife Federation, and the Judean People's Front would be producing five commercials that say, "These rockets are going to contaminate the whole world!" Unfortunately, some times I think that people want to be scared by fanatical claims of imminent {ecological|financial|terrorist-caused} disaster. By and large, humans seem to be more willing to listen to the Chicken Littles than to voices of reason.

Don't get me wrong; I would love to see us go back to the old plans for nuclear reactor-powered spacecraft. I just think that there will be gigantic and wide-spread resistance to the idea.

That was the Cassini mission to Saturn. Those thermoelectric nuclear generators have been around for years, and they're well-proven technology. Pioneer and Voyager used them too. They're not fission reactors though. They generate electricity from the heat of radioactive decay. A Russian spy satellite with one of those generators even crashed into Canada [ssimicro.com] in the 70s. It was bad, but it wasn't the end of the world.

Nice to see an old-timer get a little coverage on/., but he really covers no new ground in that short article.

The major objections then, as now, are:

- What happens if fission powered rockets crash? Instant nuclear disaster, unless the containment vessel holds (and it might, but the public will not be convinced it would).

- Other countries fears that fission powererd rockets are actually orbiting nuclear weapons, able to be dropped on them at will. And again, even if they weren't bombs, orbiting fission rockets would be nuclear weapons: all you have to do is build the containment vessel so it can be blown apart on impact via conventional explosives, leaving a cloud of contamination.

I don't predict these space nukes are coming any time soon. Better to invest in laser propultion and linear magnetic launchers.

Other countries fears that fission powererd rockets are actually orbiting nuclear weapons, able to be dropped on them at will. And again, even if they weren't bombs, orbiting fission rockets would be nuclear weapons: all you have to do is build the containment vessel so it can be blown apart on impact via conventional explosives, leaving a cloud of contamination.

Why on earth would somebody use fission powered rockets for low orbit transit? The mass and $$$ savings are only worth the hassle on long distance space travel. The focus of the article was on sending missions across the solarsystem, not to the international spacestation.

The focus of the article was elimination of chemical rockets and use of nuclear heated helium gas rockets for all launches, low earth orbit and up.

All launches would benefit from a thrust to weight ratio perspective. He did mention that if Hydrogen gas were used there would be some radioactive fallout from the gas. I imagine that would be from neutron reactions with the Hydrogen breeding tritium and deuterium as the Hydrogen is blased out of the reactor. Use of Helium instead would be less efficient but not result in any appreciable nuetron activation.

Better to invest in laser propultion and linear magnetic launchers.Lasers will be great for getting to Mars? Have you never heard of dispersion? As for magnetic launchers, did you not get the writer's point, that the goal is to accelerate all the way there?

Multiple spacecraft containing dangerously radioactive elements have already been launched. Danger exists, I don't deny it, but I'd suggest that those dangers can be overcome.

- What happens if fission powered rockets crash? Instant nuclear disaster, unless the containment vessel holds (and it might, but the public will not be convinced it would).

Oh, you mean like Chernobyl? Not to make light of 100 or so deaths, but there are worse things in the world. It's hard to get worse than Chernobyl: Big core with high burn-up (that's lots of fision products from running), Zero containment, chemical explosions and fire at ground level.

Or perhaps you were thinking of all of the thousands of above ground nuclear bomb tests that the people have performed?

- Other countries fears that fission powererd rockets are actually orbiting nuclear weapons, able to be dropped on them at will. And again, even if they weren't bombs, orbiting fission rockets would be nuclear weapons: all you have to do is build the containment vessel so it can be blown apart on impact via conventional explosives, leaving a cloud of contamination.

Holy Armagedon, Batman! Do you think that this is a more practical means of nuking your friends than the tens of thousands of purpose built warheads lying around?! What shall we do?

I suggest we quit fooling around with bullshit fears and get some good use out of Nuclear technology. Projects Kiwi and NERVA were technical sucesses killed by ludite nonsense. We can go to Mars, we can exploit the solar system and we should do so. The sooner the beter, population expands geometricaly. We can use nukes to solve our problems peacefully, or we will use them the other way as we run out of exploitable resourses here. Chose your children's future.

I very much doubt that the answer to the present population expansion lies in exploring the solar system. At current tech, it would take immense resources to keep even a few colonists on the most suitable planet (Mars). The same as a massively larger population back home.

The real benefits of exploring the solar system would be scientific knowledge and, medium to long term, mining of resources rare on Earth. Colonisation would be very long term - by current estimates, based on predictions for tech improvements, it would take 100 years and a shitload of resources to terraform Mars (based on an article I read in Focus a few years back). It's best that we wait until we really have the tech to do it well, and try to sort out our problems at home at home in the meantime.

Yes, good point. Let's all sit here on this one little godforsaken planet and hope that nothing comes along and does a number on it. There's really nothing to worry about. Aside from the natural possiblities like solar flares, asteroid impacts, ice ages, global warming induced flooding, and freak tectonic action, there's just the pesky manmade problems of nuclear wars, virulent diseases, and shoe manufacturing run amok. All of these could quite possibly wipe out our species, almost certainly our civilization, but there's really no need to hedge our bets by establishing Earth's progeny on other planets.

I realize that the odds of anything we can't handle coming along in the next few years is pretty slim to say the least, but I for one am not willing to bet the human race on it. Particularly when the potential rewards for moving out into space are so great.

When you see how difficult it is keep tiny research stations in Antarctica in operation, never mind self-sustaining, and then consider that Mars is somewhat less hospitable then Antarctica and that Mars is far and away the most hospitable place in the solar system after Earth, it's doubtful that one increases the long-term chances of the species surviving by putting it in extra-terrestrial colonies.

The best place to try to ride out a global catrastrophe is Earth. Whatever the technology that would allow people to survive off of Earth (e.g., self-contained cities, terraforming) it could be deployed with a greater chaance of success on post-apocalyptic Earth than anywhere else.

At best, one might want to store some gear on the moon as kind of off-site backup for civilization. In the event of global catastrophe, some or all of the inventory could be launched automatically to return to Earth.

It's not a question of finding a place where there are no dangers. It's about being in enough places so that the possibility of all of them being affected to a lethal degree all at once is essentialy nil. If something really bad happened to Earth, it'd be nice if there were colonies near or at self-sufficiency scattered around the solar system (and beyond?) that could build anew.

A line from "A Deepness in the Sky" by Vernor Vinge that stays with me is the one about Earth having been resettled from scratch three or four times since mankind achieved starflight. Each previous incarnation of civilization having been destroyed for one reason or another.

Thousands of birth defects? Who told you that, Greenpeace? Here [fjokk.hu] is a nice sober paper for you. Outside preventable exposures in radiation workers and children, there are no statistically noticible differences.

I've read the World Health Organization's ten year report and I'd point to it if I could. Unfortunately, that one and a new one are not free information. Order it [who.int] or go visit a library.

I'm not going to say there are no risks, what I'll ask you to do is weigh the risks of doing nothing. The shutdown of the US space program is a national embarassment. We beat up all the lions, tigers and bears. Even the baboons gave up (Appologies to W. Chruchill). The world is watching us and they expect results. We should show them that it is better co-operate and create new resources than it is to squabble over and destroy old ones. If we wait too long, we may no longer be able to afford the effort.

Maybe you could design it such that the launch apparatus is like those used today, but breaks off after exiting the atmosphere, where nuclear propulsion commences. (IE, you release no neutrons in to the reactor until the craft is a specified number of miles outside our atmosphere).

Even if it is practical, here's a comforting thought if you were an astronaut:
"Yay! We're going to Mars!... And we're propelling ourselves using the worlds largest (hopefully controlled/directed) nuclear bomb!"

"Maybe you could design it such that the launch apparatus is like those used today, but breaks off after exiting the atmosphere, where nuclear propulsion commences. (IE, you release no neutrons in to the reactor until the craft is a specified number of miles outside our atmosphere)."

The whole point is to ELIMINATE chemical rockets and go to fission rockets. The vast majority of the work is done getting to low earth orbit. Thats where it makes the most sense to use a much higher thrust to weight engine.

The reactor shielding required for a manned spacecraft is pretty large. There isn't any particular mass savings through using a nuclear power source... most of the mass for a deep space mission is reaction mass, and the specific impulse developed by a nuclear rocket is only about 2 times that of a chemical rocket... reaction mass savings ends up being on the order of 75%, but this is offset by the increased payload/structural mass.

Now, if someone could finally get fusion rockets to work, I think we could finally go someplace. But I am skeptical about using fission for manned missions.

First, your reaction mass is your reactor shielding. There's a whole lot of water or liquid CO2 between the pile and the crew.

Second, the craft only has to carry reaction mass for one way. You get to Mars, you turn on your compressor (powered by your atomic pile), and pump the local atmosphere into your tanks. This is a huge advantage. CO2 provides a lower specific impulse than, say liquid H2, but it's plenty to get back to Earth, or to push on to Titan.

In short, there are huge advantages to a nuclear rocket over a chemical rocket. Check out NERVA and NIMF, the two best treatments of the subject.

"During his long NASA career, Mr. Hickam worked in propulsion, spacecraft design, and crew training, and won many awards including the Astronaut Office's coveted Silver Snoopy award for his outstanding support of the astronaut corps, and a special commendation for overall excellence from the Director of the Marshall Space Flight Center. His specialties at NASA included training astronauts on science payloads, and extravehicular activities (EVA). He also trained astronaut crews for many Spacelab and Space Shuttle missions, including the Hubble Space Telescope deployment mission, the first two Hubble repair missions, Spacelab-J (the first Japanese astronauts), and the Solar Max repair mission. Prior to his retirement in 1998, Mr. Hickam was the Payload Training Manager for the International Space Station Program."

"Like many of you, I wanted to be an astronaut when I was young. It wasn't the glamor of a high profile, high risk job. It was the adventure. I lost that dream sometime during my teen years, when I realized that I wasn't enough of a Superman to join America's astronaut corps. But hope springs eternal. With the increasing availability of space flight in the 21st century, and the advent of a commercial tourist industry in space, I may yet manager to make my way into the high frontier."

Now, if someone could finally get fusion rockets to work, I think we could finally go someplace.

No one has been doing research on nuclear rockets for 30 years. How long will we let our fear keep our technology from advancing? We can make "bunker busters" and reactors that fit in the bed of a truck. What if some of that effort and those new developments were applied to nuclear rockets? Would they be smaller? faster? safer? You bet.

But I am skeptical about using fission for manned missions.

How long will our fear make our decisions for us? How long will we hide in the closet with the blanket over our heads awaiting the impending World War III? How can we know if a safe manned mission can be designed if our fear prevents from doing any research at all?

It is clear that nuclear power has an energy density far superior to any chemical rocket. It is clear that we will never do anything useful on the moon or mars if the only way to get there is the Saturn V.

If it weren't for Da Shuttle, we could have had Moon bases by now. The Saturn V could take crews and payloads to the Moon -- Shuttle can barely make low-Earth orbit. Saturn launches probably run a billion dollars each, but each Shuttle launch runs a cool half billion, depending on who is doing your accounting. Besides, the Saturns were already designed while with the Shuttle they had to sink in several billion to get it going.
Budgeting, say 3 billion a year, doing 3 launches a year to the Moon, by now you could have had over 30 years tons and tons of stuff delivered to the lunar surface. Instead, this same money was pissed away on the Shuttle and the stupid space station.

AFAIK, the book is mostly the story of his life, with some embellishment here and there and presumably some stuff left out to make a better story. The book is upfront about this, and some of the names were changed so as not to embarrass anyone who might come out in a bad light.

One scene in the book that is made up (as I recall) was the one where he saw Sputnik passing over West Virginia. Apparantly it never happened, I think it was cloudy that day, even though it was the catalyst (in the book) for him wanting to build rockets. That scene also gave the movie its title, looking up at the "October Sky" and seeing Sputnik.

Whilst nuclear is one option to get us out there, particularly to the furthest planets, I don't agree that this is necessarily the way to go.

Putting the supposed issues of launching nuclear rockets to one side, all of the issues we know of will be solved by using the existing resources of space, rather than trying to launch every little thing from the earth. Right now we are doing the space equivalent of driving from East to West coast America, whilst carrying all our gas with us for the whole trip. Ever heard of gas stations?

NEOs and the moon have plenty of fuel for us to use, and if you refuel in space, the maximum distances we can go are enormous.

The other issues also become non issues. Radiation? A few tonnes of shielding isn't a problem if you have enough fuel. Gravity? Spin your spacecraft on a tether, and simulated gravity is plenty good enough [the only reason that this isn't proposed right now is mass constraints, also they want zero-g in the ISS for example]. Again, use non terrestial sources for materials, and most issues are gone.

Nuclear is an entirely safe and reasonable approach. But it's not a necessary one. And politically there are huge issues; for what are mostly dumb reasons. But we have to deal with dumb reasons, held by misguided people in life.

This article doesn't really cover any new ground, and is lacking any real details...it's more of a generic endorsement from a celebrity scientist than anything.

I think the idea of going to Mars is wrong headed. I don't think an exploration of Mars will lead to great new developments for humanity. I don't think the idea of colonizing Mars is practical, and if it was, it certainly won't help humans on the Earth. I realize Apollo R&D helped lead the push towards creation of ICs, but I think any R&D budget would be better spent elsewhere...

Specifically, I hear about the idea of terraforming, which even with the most advanced technologies would take a ridiculous amount of time, even if it's possible to replicate the complex necessities of Earth conditions on a planet wide scale. Or the idea of releaving overpopulation through colonization, which is so silly it can be freely ignored.

Mr. Hickam seems to assume everybody shares the dream of having people live in a big plastic bubble far away...and the enormous cost, as well as the very real threat of putting nuclear reactors in ships that tend to blow up in the atmosphere, are insignificant. It's an odd viewpoint that he doesn't bother to justify. Will it make people's lives better? Should it just be done because it can? Manifest Destiny in space is so sci-fi.

This was one of Kennedy's four goals during his Special Message to Congress on Urgent National Needs [umb.edu] (a.k.a. go to the moon speech). He said that it gives "promise of some day providing a means for even more exciting and ambitious exploration of space, perhaps beyond the moon, perhaps to the very end of the solar system itself".

The nuclear rocket is probably the best choice in large distance exploration that we have right now. Solar power becomes useless pretty much past the Earth and no other power source can pack the mass to power ratio that nuclear power can. If we want to go big, we have no choice but to use a nuclear rocket or take a long, long time. The weight issue in rockets is a big deal, so alternate propellants are out since they will take up to much weight for the same power.

For close distance exploration (i.e. the moon) I don't really see a nuclear rocket taking any part. While obviously it could achieve its goal, its a little overkill for the purpose (and considering the fact that if it were a direct exhuast type it would have a plume of activated radioactive materials, assuming it uses water as a propellant, it probably wouldn't be that popular).

I hope this happens, and I've been hoping for a long time. Its our only real chance to get off the earth permanently at the present time.

Nuclear power is not a clean source of energy as alleged in this article. The mining, production and disposal of nuclear material makes it one of the more dangerous forms of energy production. The material used in reactors remains dangerous (ie. life threatening) for hundreds of thousands of years. How can anyone (apart from dubbya) define this as clean? Sure there are no smoke stacks, but come on!

As a uranium producing country, Australia has seen a number of 'mishaps' in relation to uranium mines. Admittedly, most of them have been relatively minor, but they demonstrate that no human activity is 100% failsafe, and the potential for massive disaster is huge when compared to other forms of energy production, fossil fuels included. Of course, this does not diminish the need to find alternatives to fossil fuel sources, they are dirty and finite (ie. unsustainable). Nuclear energy is not an appropriate response, though.

Also, beyond the production and disposal of nuclear material, what happens when something goes wrong with the rocket itself? Could you imagine a nuclear version of the Challenger disaster?

I'm as much of a technocratic utopian as any other/. reader, but even I realise that the use of technology, and its impact on society, is more important than any geek factor.

wrong. Imagine all the waste of all nuclear plants in the US combined over their lifetimes. It will fit in a football field stacked up a few stories high. Now imagine all the waste of the same power source (equivalent) of coal-fired power plants. Where is the waste? Everywhere. With Nukes, you know where the waste is. The most environmentally friendly power source is nuclear. Now imagine all the windmills it will take to equal one Nuke plant. I am looking at 3 of them now from my back yard at TVA's Buffalo Mountain project. It will take 3 thousand of them which will leave absolutely no mountain, trees, or anything else for that matter. Get real man and get out of your closed world.

There are many places where you can put those windmills without cutting down trees.
There are many places u can put solar panels.
Sorry but there are so many more environmentally friendly powersources.

There's a very dirty (quite literally) secret about coal burning few people talk about: the fact it releases a substantial amount of radioactive material into the air. People forget that trace amounts of radioactive elements exist in many forms of coal.

Nuclear power is not a clean source of energy as alleged in this article. The mining, production and disposal of nuclear material makes it one of the more dangerous forms of energy production.

How many people have died due to gasoline fires? Oil well mishaps? The fact that people can be harmed by a technology is not a good reason to not pursue the technology. As with everything, we must minimize the risk and get on with life. As you say, no human activity is 100% failsafe. We are now, and will continue to produce nuclear material. The amount of nuclear material used in rockets will be very small compared to the amount used in power plants worldwide.

Also, beyond the production and disposal of nuclear material, what happens when something goes wrong with the rocket itself? Could you imagine a nuclear version of the Challenger disaster?

A fundamental design requirement of any nuclear reactor is that it must survive re-entry intact. Nuclear fallout is simply unacceptable. Tests can be performed. Take the reaction vessel, fill it with a volatile liquid, and drop it out the ISS airlock. If none of the liquid escapes and the vessel is recovered intact, then it's good enough to house nuclear material.

Again, this is simply a design requirement, and not a good argument to stop all development of nuclear rockets.

Nuclear is practically a dirty word. Just stick your head out the door and say it, and in 5 minutes you'll have at least 5 hippies protesting outside. They won't know what or exactly why they're protesting, but it has the word "nuclear" attached to it, so it must be bad.

It's the same way with health nuts and the word "chemicals" though they don't protest it, they just condemn it. Just walk up to someone in a health club, and ask him, "Do you know how many chemicals you have floating around in your body?" and watch him get a disgusted look on his face like you accused him of having herpes. Or ask some clerk at a health food store, "How many chemicals does this have in it?" and laugh at his ignorant @ss when he tries to claim there aren't any.

Do these "hippies" know about physics and engineering design involved in fission power plants? Maybe ask them have they gone through the US Navy nuclear propulsion training program, where you learn everything involved in fission power plant design, including all the pluses and minuses of various reactor designs.

If you want to blame the problems of nuclear power blame it on the former Soviet Union. Between poor reactor designs, insufficient safety factors (besides the Chernobyl accident, the Soviet Navy lost several submarines due to reactor accidents), and nuclear waste storage in open pits, they should be faulted for doing all the wrong things about nuclear power in general.

Actually (and very OT), you'd have a good chance of being right if you accused those health nuts of having Herpes too - 60-90% of the world's population has been infected with Herpes Simplex Virus 1, and it tends to kick around in a latent form. Furthermore, you could also tell them that 1% of their genome consists of viral inserts, and that therefore they are a GMO (sorta), but they might not thank you for it.

Correct, for the most part. I was going to make your post. I would add a minor correction, however. The amount of the genome made up of viral-DNA is more in the low double digit percentage. If you count retrotransposable elements, VERY closely related to retroviruses (like LINE1 elements) the number of those alone is 17%. Throw in Alu elements, SINES, Ty elements...you are talking a not-insignificant portion of the genome.

We have a hippie-type in my Alpine Environments class (I've been made fun of enough, no need no need). This guy is seriously f*cked in the head. He probably comes to class on acid or something. Anyway, we were discussing how solar radiation intensity (insolation) varies as a function of altitude, and the impacts on snow conditions, and this guy jumps up and yells out:

The best a chemical rocket can do is get up to
speed (burning up all its propellant in the
process) and then drift to its destination, like a
car coasting down the highway with its engine off.
What's needed are space drives that will provide
a constant velocity.

So what's the difference between drifting and moving at a constant velocity? Spaceflight
analysis really shouldn't be done by people who
fail to distinguish between velocity and
acceleration.

The thrust required to correct a well-planned interplanetary orbit could be accomplished by having an astronaut piss out the ship away from the direction they need to go.

Really, any halfway decent orbit would barely be affected by solar wind and dust particles. The overlapping gravity effects are terribly hard to figure out, but they can be done well in advance on any computer and accounted for fairly well. Note that most comets have very safe and regular orbits despite never correcting theirs.

The best a chemical rocket can do is get up to speed (burning up all its propellant in the process) and then drift to its destination, like a car coasting down the highway with its engine off. What's needed are space drives that will provide a constant velocity.

As any high school physics student will tell you, burning up your fuel and then "coasting" the rest of the way means that you're at a constant velocity. Velocity is a vector, with two components: Speed and direction. In space, there's no (significant) drag or friction, and so your velocity is constant. If you were to keep burning fuel, you would keep accelerating (assuming an infinite amount of fuel) which anybody will tell you is not a good thing when you eventually want to stop.

I see no reason to listen to somebody talk about physics when he clearly has no respect for the language.

Yes, and as any high school physics student will tell you, if you have no fuel, then the only way you have to stop, rather than flipping end for end and applying thrust, is to hit something.
Any high school physics student will also tell you that you WANT constant acceleration, NOT constant velocity, because you'll get to your destination faster. After all, all you need do is flip end for end at the half-way point to your destination, and turn your engines back on.
Or, put another way, the sudden stop at the end of a fall at Earth normal gravity doesn't hurt because you're travelling at 9.8 meters per second; a one second fall will leave you bruised. No, the sudden stop hurts because you're accelerating 9.8 m/s per second.

If you were to keep burning fuel, you would keep accelerating (assuming an infinite amount of fuel) which anybody will tell you is not a good thing when you eventually want to stop.

Don't see why I should respect you when you think Newton's laws are still absolute. Einstein, as you may recall, debunked your statement by saying even if you keep accelerating, you cannot pass the speed of light. Your acceleration therefore cannot be constant at a constant burn rate, but changes as you start going fast enough for time and space to show the effects of relativity.

Actually, we're both right. The velocity vector can be represented by two components: the magnitude of the vector and the (three dimensional) unit vector indicating the direction. The velocity vector can also be represented by an ordered set of 3 components, indicating the x, y, and z magnitudes, from which you can then derive the form I wrote.

For example, let's say that I'm moving at 30 MPH, and going in a direction due North and vertically (z-axis) at a grade of 10 degrees. That describes the velocity vector perfectly.

Alternately, I can say that I'm moving in the North/South direction with (30 MPH * cos(10)), assuming North to be positive, moving East/West at 0 MPH, and vertically at (30 MPH * sin(10)). That's your three-ordered pair (x,y,z) magnitudes.

Both representations perfectly reflect the vector in question; you say po-tay-to, I say po-tah-to. Don't mess with the physicists:-)

Look... the guy was going great guns until he got hired by NASA. Now he's a media celebrity mouthpiece for them. He probably should have followed Von Braun out the door even though Von Braun wasn't his hero. Von Braun can't be as bad as the scum that took over and made NASA what it is(n't) today.

The whole space program is still following its trend of keeping large modules as a whole.The whole premise is: "if we have one large system that has few parts then less can go wrong". That is an obviously flawed system as many things still go wrong. In fact the systems that have been designed as modularized have only failed once (space shuttle O ring, 1986. Where as the moon lander never once malfunctioned). Most problems in space happen due to problems not with main systems but to smaller malfunctions like a clogged pipe (not inherent in the design or function of the overall system).But I digress, outer space is not a good environment for large thurst engines, smaller long lasting engines are good. That compares to the large engines required to leave Earths initial gravity. Again, we try to adapt one engine to both systems.As previously posted, high thurst reusable efficient engines for getting a space ship out of our atmosphere and into a different environment (you don't see me driving a car in the Marianas trench).The reasons that modularized systems don't fail is because we think they're going to fail so we study them to death and make them really safe, thus no failure.

It is really annoying when some one arguing from authority (i am a rocket scientist, listen to me) gives you misleading information.

Nuclear engines are much more dangerous than chemical ones.

If a chemical rocket develops problems on ascent ground control push a button and blow it up.

What if that rocket has a shitload of uranium or plutonium on board?

We have sent nuclear material up in rockets withsome nuclear powered stelites but they have a really negligable ammount of radiactive stuff in them, compared with what is needed for a mission to mars.

And if you think that rockets do not blow up on ascent any more you have not seen NASA's record recently.

So there you have it - thats a risk that he did not mention although it is a very relevant factor. Now you may say - the risk is not that great, or it is worth it, but it should have been mentioned in an honest article.

And also the thing he said about getting energy from space is such BS. If he knows as much about nuclear power as he pretends to he should know that we have enough uranium to give us energy for a loooong time and nuclear powerplants are much safer than nuclear rockets.

Perhaps, but I'm hoping that habits will change pretty soon. If you look at the ever-growing effectiveness of renewables, there's real reason to hope for a genuinely clean solution. Even at present tech, Germany gets 50% of its energy from them, and they (particularly wind turbines) are getting cheaper and better all the time.

Long term, though, I'm still hoping for fusion. Between that and fuel cells, we could (theoretically) use massive amounts of energy while only endangering ourselves a fraction as much as we do today.

Nuclear engines are much more dangerous than chemical ones. If a chemical rocket develops problems on ascent ground control push a button and blow it up. What if that rocket has a shitload of uranium or plutonium on board?

But why would we want to blow it up? It's not like it's full of rocket fuel or anything - it just has some radioactive stuff in it. The radioactive stuff is solid, and even if we make a full-acceleration nosedive into basalt (which we won't, because all we have to do to stop the thrust is dump the reaction mass, not to mention parachutes), the worst that's going to happen (assuming decent reactor design, like a pebble bed reactor, if they scale that small) is that you get a few chunks of radioactive material; there isn't enough energy involved to get a pulverizing effect. Men with geiger counters go find it and clean it up.

Nuclear rockets are safer than chemical rockets (provided that the reaction mass used is something basically low-energy, like CO2 or H2O, rather than H2 or H2O2). It's like the difference between a low-pressure solar steam engine and a dragster running on nitromethanol, and you're asking about what to do if the steam engine catches fire because of the flaming exhaust it doesn't have. The risk of boost-phase abort requiring the destruction of the craft in atomic rockets is very, very low.

If you want to have something to attack nuclear rocketry on, look into on what effect the very slightly radioactive exhaust trails will have in the ionosphere. Man-made Van Allen belts? Could be, if there's enough energy. Would there be? What would those do? How radioactive would each particle of reaction mass be? How many of them would there be, and what would happen to them, during the atomic rocket's atmospheric boost phase? What kind of reactor would it have? What are this reactor's modes of failure? Is there a reactor that is, by design, immune to modes of failure we want to be particularly concerned about?

Not all of these questions were addressed by Hickam, either, but that doesn't make the article dishonest.

Space travel with chemical rockets just barely works.
You need too much rocket to lift too little payload.
The excuse for space travel we have now works, such as it does, only because of desperate weight reduction, narrow safety margins, and throwing away much or all of the vehicle during each flight.
This hasn't improved in thirty years, and it's not going to. There are basic limits to what you can do with chemical fuels, and they were reached long ago.

This guy is right. And it's sad.

A fission rocket could work. Working prototypes were built in the 1950s. But the safety problem seems hopeless. A crash would be a major radioactive mess, and eventually, a crash is likely.

Anyway, nuclear rockets are a great idea. A better one, you may have heard me harp on this before, is VASIMR. It is a plama rocket with a nuke power source. It will be around ten times as efficient as the nuke rockers. However, the VASIMR, unlike the nuclear rocket, it does not have enough thrust to launch from earth. It is more a slow and steady engine that runs for weeks instead of minutes. But the burnout velocity of a VASIMR can be vastly higher than a chemical rocket.
The nuclear rocket can provide cheap, efficient space launches with not too much radioactive fallout. In fact, if a nuclear rocket using helium as a propelent will produce no fallout at all. Since a nuclear rocket is about twice or three times as efficient as a chemical rocket, the amount of fuel you'd need would be slashed dramatically. A nuke rocket launch might only use 10% or less of the fuel that a conventional booster would.

It's under R&D.

It ionizes hydrogen with microwaves an then accelerates them with magnetic fields. While it doen't provide thrust like a chemical rocket, it certainly has many, many times more thrust than a ion engine. It has some oomph to it. For cheap launches, you really need somthing like the x-42 scramjet spaceplane. That would cut costs of launching by a factor of 10 with no giant lasers.

VASIMR will get a specific impulse of 30,000 seconds compared to 500 seconds for the shuttle's engines. A specific impulse is the number of seconds 1 kg. of fuel could produce 1 kg. of thrust. The specific impulse of the VASIMR is 60 times better than the shuttle. That is many times better than the ~1500 seconds you'd get with the nuclear rockets.

That would allow cheap interplanetary voyages anywhere in the solar system, using very little fuel. Using these engines, you could get to Saturn in less than a year. It would also allow slow intersteller trips of around 1% the speed of light.
Also, VASIMRs could be easily, cheaply, and quickly refueled for more missions.Interplanetary travel could become cheap. I bet each ship would cost around 5 billion dollars initialy. After that, it's cheap. After each trip, an X-42 could come and restock the ship with fuel and supplies. That would only cost around 50 million. We could send tens of thousands to colonize Mars.

BTW: On this article, it says the VASIMR gets 10,000 seconds. It can reach 30,000 with further development.Read about the VASIMR here [space.com] --

NASA is already sending out hydrogen ion stream rockets, using the magnetic ionizer you're describing. It is a complete success, and many times more efficient than traditional rockets.

As for a scramjet launcher... that is silly. You don't save a lot of money. The major expense in a launch is not the fuel, it's the craft. A reusable craft does not always result in a cheaper launch, because that requires a fancier craft. For example, Shuttle launches are more expensive than disposible rocket launches.

Saturn in a year claim is dubious. Ion propulsion gives slow, steady, efficient thrust, perfect for long cheap trips, but terrible at fast acceleration. Though a combo with chemical early stages, and ion later stages, might work well for a fast distance trip. The actual thrust in the Deep Space craft using ion propultion is about the weight of a sheet of paper... but that really adds up over a few months!

The point isn't that your saving money on the fuel the point is which launch system you use. A nuclear rocket is not carrying as much mass in fuel as a chemical rocket. While launching a chemical rocket capable of interplanetary transfer may require a launch vehicle the size of an Arienne-5 a nuclear rocket which has less mass may require only a pegasus.
-Mishra

Yes. Slow intersteller trips. The ship would probably be passed en route by faster ships. However, it is an easy way to send huge quatities of materials to other stars. .1 C would be nicer for fast manned missions or probes. That would mean 40 years to Alpha Centauri. That is doable, but would require an enormous amount of fuel.
To reach.1 C, you can use several different methods.

1. Fission fragment sail or reactor.Uses thin films of highly fissionable Americium as fuel.
The fission fragments from the nuclear reaction escape at very high velocities, propelling the ship very fast. You can't use plutonium in this setup because it cannot fission when formed into thin films. You need thin films for fission fragment propulsion so the fragments can escape.

This setup can reach a specific impulse of 1,000,000,000. 2,000 times more efficient than chemical rockets. However, this gets too expensive when you scale it up beyond a small probe. Americium is fscking expensive, millions of dollars per ounce.

2. Fusion
Fusion's great. Once power fusion reactors come on line, the fuel will be cheap.
There are several different fusion concepts. The closest to being realized is the ant-matter catalyzed fusion type. It blows up little fusion pellets at it's rear. This uses fusionable pellets of Deuterium and Tritium that are surrounded by uranium. A very small quatity of antimatter is fired at it. This starts the fission which then starts the fusion and causes the whole thing to explode.
This could be built in 20 years. Everything is here except the antimatter. You only need a few micrograms of antimatter. We could be producing that pretty soon. It could theoretically reach 200,000 seconds.
There are other types of fusion rockets that could reach 1 million seconds. These use magnets to confine the fusion plasma. Some is leaked out the back for propulsion. However, it's hard to build a self-sustaining fusion reactor. Plus the magnet weight (1,000 tons) would have to be reduced dramatically to be practical at all. That's about 50 to 70 years away.

3. Antimatter-matterEfficiencies of 10 million secondsA helluva long ways away. We don't know how to begin producing enough anti-matter.

4. Beamed energy
In the distant future, the best thing for fast intersteller flight.
Just a couple decades down the road, we could build Robert Forward's starwisp probe. It would be 6 kilometers wide and be made of a fine mesh. It would weigh 42 grams, if you can believe that. It would be easily propelled to.2 C by a 10 gigawatt beam of microwaves from an orbital power station. Very easy to do, especialy if we have nanotech.
For manned flights, you need gigantic solar arrays around the sun. Here, I'll talk about a project for a Class 2 civilization. That means one able to harness the power of an entire sun. Say, 100 years down the road, we decide to have thin-film photovoltaics constructed around the sun. That would capture around 1 octillion watts. Anyway, autonomous self-constructing robots and nanobots would get the materails off a large asteroid and begin constructing this. Being very thin solar cells, you'd only need maybe 1,000 square miles of materials. After a few years, we would have a working Dyson sphere.
Some of the power, maybe a quintilion watts could be funneled into lasers and broadcasted to a giant gold-foil sail the size of texas or the US or even much larger. The laser would be able to propel it to.9999 C. The gold-foil sail would be only a couple atoms thick, and supported by a scaffolding of nanotubes. The sail would weigh only a few thousand tons. The payload could be a million tons. That sounds fantastic, but an extremely advanced civilization with nanotech and AI could easily do it.

Anyway,

.01 C like you can reach with the VASIMR would be excellent for intersteller resupply, or sending huge numbers of people for colonization.

I remember reading about a Bussard ramjet, a proposal for possible future interstellar travel.

The idea is that since interstellar space is not empty, the craft will not have to carry all its own fuel, but can rather use huge magnetic coils (around 10^6 Tesla in strength) to gather its own fuel. It would have to carry enough on-board fuel to reach a certain threshold speed, at which point it begins moving quickly enough to pass through enough space in a given time to gather all the fuel it needs.

It would work by 'funneling' hydrogen, which is the most available (though by no means is it plentiful) gas in interstellar space, into a fusion reactor. Needless to say, this is a long way off, if it will happen at all, but it's a really nifty idea.

Some quick searching reveals a quick once-over here [woodmansee.com] and a more mathematical treatment here [dangermouse.net].

The problem with.999c is that friction (space isn't a perfect vacuum) would melt/vaporize all known materials, so how do you construct a ship/probe that can handle that speed? IIRC, at.3C all known materials melt due to friction...

Once at the target star system, a Dyson sphere can be constructed around that star.

Yup, just whip a handy-handy Sears Roebuck discount Dyson Sphere out of your back pocket, follow the directions, and you'll have your own private Dyson sphere in minutes, just like on the movies... no worries, mate! (-:

Um, no on almost all counts? True, that was a poor choice of words regarding 'constant velocity'. But nuclear engines are fantastically useful in space since they can run for a very long time on little fuel; all you need is reaction mass. Unless you actually want a 2 year trip to Mars, chemical drives require too much fuel and cannot be easily refueled at the destination. Nuclear drives would only require more reaction mass, easily acquired from nearly anything with an atmosphere. Solar sails are great for accelerating, but you can't decelerate at the end, and they're slow as molasses at absolute zero anyway. Nuclear drives are particularly bad for gravity well operations, since they are far better suited to long term, low thrust operations. Lastly, fusion may be cleaner than fission (though in space, who cares?), but it's irrelevant because the technology is nowhere near available for this kind of application.

There's no friction in space. Strictly speaking, there is some, but you wouldn't notice it unless you were pushing c. The Sun does suck everything in, but in going from one planet to another you are just shifting your existing solar orbit, not really 'fighting' its gravity well.

Now, how fast you can get there depends on how far away and how fast and how long you can accelerate. The quickest route would be to accelerate for the first half, then turn around and decelerate for the second half. There's nothing to really slow you down so unlike a car, you have to do that last bit yourself. But our spaceships are sooooo primitive that they can only carry enough fuel to accelerate for a little while, and the final speeds may still be low enough for an aerobrake at the destination. That is, you enter the outer atmosphere of the planet where there most certainly is friction and you'll slow down enough to enter a stable orbit.

Space is a very wierd place to be new to, since there's no good analogies for it here on earth. A seagoing vessel is fairly close; once you get a big ship moving it takes a while for it to stop or a lot of effort to stop it quickly, but the analogy fails on a number of other points (maximum speeds, hull shape requirements, steering, etc).

You still really don't want any sort of radiation or radiation leak in Antartica, even if the risk might be low. One thing history has taught us is that statistics might make us feel safe, but we rarely are. We also grow complacent, and then disaster befalls us.

However Antartica and the Artic would be an ideal place to build a rail-gun transport system, using magnetism to build up speed and takeoff velocity. Getting up to speed from nothing is by far the most fuel consuming part of the process.

Once you leave the launch ramp, you can use conventional Liquid Oxygen/Hydrogren fuels to get out of the atmosphere. LOx & LH are probably the BEST choices for use, simply because the byproduct is water, and not a pollutant like most of the other propellant mixes. And dropping water vapor over the polar cap is not going to do it any harm, more likely do it some good.

The cold is a useful ally for such a setup. Less energy required to put oxygen and hydrogen into a liquid form, an abundance of water for producing oxygen and hydrogen via electrolysis, and a huge amount of wind and solar energy that can be harvested for power (in the right locations). There is also the semi-conductor properties that some substances exhibit in cold conditions that could be exploited.

Once launched, an orbiting docking facility can then fuel up a craft for longer hauls. With decent designs, the propulsion unit would be separate (and have a standard docking system) allowing changeover in orbit for another unit more suited for the job at hand, such as a nuclear propulsion unit for intra-solar missions, or one of the many other propulsion systems that are in the works.

If someone comes up with a smaller or more efficient engine design, a standard docking system between the propulsion unit and the craft allows easy retrofitting and upgrading. Craft returning to the Earth can bring back propulsion units so they can be tested, retrofitted, refueled and relaunched on the next craft.

Same reason we keep buying new computers even though we know it'll be outdated by the time we get it home. We have to do something or we'll forever be sitting at home saying, "Just one more doubling of processor speed and I'll upgrade". A bird in the hand is worth 2 next year, as it were.